DK161603B - HOT MELTABLE COMPOSITIVE FIBERS WITH A POLYPROPYLINE CORNER AND A POLYETHYL COVER AND METHOD FOR PRODUCING IT - Google Patents

Description

DK 161603 B

The invention relates to hot-melt composite fibers which can be further processed into a non-woven fabric by heating or the like, to provide a bulky product with a soft grip, and a method of making it.

It has been many years since heat-melting composite fibers were invented on a side-by-side polypropylene basis, comprising two components having different melting points, and for which a significant portion, e.g. half or more than half of the surfaces thereof are occupied by the lower melting point component. Essentially, such improvements have been intended to improve the shrinkage properties of a web by processing the fibers into a nonwoven fabric by heating and to improve the strength, volume and similar properties of the resulting nonwoven fabric, and many have been obtained. good results, but the results have not yet been satisfactory in terms of volume sensitivity.

So far, no satisfactory results have been obtained, either in terms of volume or in the grip of nonwoven fabrics produced from the polypropylene-based hot melt composite fibers upon heating. Attempts have been made to improve the grip by using fine denier fibers or by increasing the proportion of other fibers to be blended with composite fibers such as rayon or wool, but this has not yet resulted in a product which stands out by good softness and volume. Thus, as the situation is, there is a great and unsatisfied need for further improvements, in terms of volume and softness of non-woven fabrics for use, e.g. paper diapers 35 or sanitary materials. Thus, there is a strong desire to satisfy this need.

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2

It is an object of the invention to provide hot melt composite fibers which can meet the aforementioned needs and which can be easily treated to a nonwoven fabric by heating due to their heat meltability, which non-woven fabric should not only be bulky. but also must have a high degree of soft grip.

As a result of intensive and extensive studies carried out to fulfill this purpose, it has been found that the nonwoven fabric structure is highly stabilized and sufficiently voluminous, gaining a soft grip when the composite fibers being treated for the non-woven fabrics, is constructed using a core portion which provides the nonwoven fabric for volume, and a 15-piece portion that makes the fibers hot-adhesive, and it has further been found that the soft grip becomes even better when in addition to the structure previously described, a number of nodular aggregates consisting of the sheath component are formed on the surfaces of the fibers except for the portions thereof which are bonded together.

The composite fiber of the invention, which is of the kind set forth in the preamble of claim 1, is characterized by the feature of the characterizing part of claim 1.

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The process for producing the composite fibers of the invention is characterized by the method of claim 5.

The composite fiber according to the invention is described in more detail below with reference to the drawing, in which: FIG. 1,2 and 3 are schematic cross-sections showing the cross-sectional structure of the hot-melt composite fibers of the invention, and

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3 FIG. 4 is a sketch showing images of the sheath on which nodular agglomerates are formed.

Referring to the drawing, reference numeral 15 is a core portion (hereinafter simply referred to as the core) of the side-by-side composite fiber comprising core portion zones 1a and 1b, each consisting of a core component of its own polymer on polypropylene. -basis. The core 1 of the side-by-side composite fiber may take various forms. Eg. For example, the core 1 may have a cross-sectional structure which is diametrically divided into two identical semicircles, as shown in FIG. 1. Alternatively, the core 1 may have a cross-sectional structure where a core portion zone 1a is mostly surrounded by the second core portion zone 1b, with the exception of a small peripheral portion thereof, as illustrated in FIG. 2. In most cases, the core actually assumes a structure that lies between the previously specified exterior outer structures. As another alternative, the core 1 may be located outside the center of the cross-section of the fiber, as illustrated in FIG. Third

Polypropylene-based polymers represented by crystalline polypropylene may comprise copolymers of propylene with a minor amount of other alpha-olefins except propylene such as ethylene, butene-1 or pentene-1. In this case, it is preferred that the content of the comonomer component does not exceed 40% by weight.

Such polypropylene-based polymers are used as the core components of the respective core subdivisions 1a and 1b, and they differ from each other in terms of the Q value, which is a numerical value expressing the molecular weight distribution of polymers and which is calculated by formula: 35 Q - Mw / Mn wherein Mw is the average molecular weight by weight and i

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4

Mn is the average molecular weight by number.

The core component of a core part zone 1a (hereinafter simply referred to as component 1a) has a Q value of at least 6, for which polypropylene is commonly used. The core component of the second core portion zone lb (hereinafter referred to as component lb) has a Q value of up to 5, preferably from 3 to 5.

The composite ratio of the core components 1a and 1b which constitutes the core 1 is between 1: 2 and 2: 1. -

The composite structure of the core side-by-side core 1 comprising components 1a and 1b with different Q values 15 informs the composite fibers of the ripples resulting from the fiber-making process as well as the ripples that develop from latent ripples by a subsequent heat treatment, which results in an increase in volume.

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Reference numeral 2 is a sheath portion (hereinafter simply referred to as the sheath) which is constituted by a sheath component of one polymer based on polyethylene, the melting point of which is at least 20 ° C lower than the lowest, melting point of the 25 melting points of the two core components. the core 1, namely components la and lb, (or the common melting point of components la and lb, if there is no difference between the melting points of these components). Such a polyethylene-based polymer may comprise polyethylene or an ethylene / vinyl acetate copolymer having an ethylene content of 98 to 60% by weight. The polyethylene in question is. exemplified by low, medium or high density polyethylene.

The composite core-type composite fibers of the invention are produced by covering the core 1 with the sheath 2 in such a way that the proportion of the sheath 2 is in the range 25

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5 to 55% by weight, based on the total weight of the jacket 2 and the core 1. When the proportion of the jacket 2 is below 25% by weight, the strength of the resulting nonwoven fabric was reduced to such a low level that some practical problems. On the other hand, with a proportion of the sheath 2 exceeding 55% by weight, the development of ripple originating from the core 1 is inhibited so that the composite fiber ripples are insufficient and the resulting non-woven fabrics exhibit a low volume density.

10

As described above, the jacket 2 is a low melting point polyethylene polymer, and the adhesive member between the fibers can be formed by heat treatment in the same way as with the conventional heat-meltable composite fibers.

As long as the sheath 2 meets the previously stated sheath requirement that it must be of the previously specified structure, a nonwoven fabric product obtained from the hot melt composite fibers of which it consists, together with the core 1, may have a sufficient volume. and it has an excellent grip. However, the structure given below may give the nonwoven fabric product a much softer grip. More specifically, this structure comprises many parts of the casing 2 which form a plurality of nodular assemblies 3 consisting of the casing component and formed by a heat treatment at a temperature between the melting point of the casing component and the lowest temperature selected from the melting points of the two core components. 30 components 1a and 1b (the parts in question can be called the aggregate parts here). In the aggregate portions, the sheath 2 is released from the core 1 or it is detached from the core 1 due to the weak intermediate affinity. The aggregate portions can be distinguished from the other portion, depending on whether or not the nodular aggregates 3 consisting of the sheath component are formed by the heat treatment at the previously specified temperature, as illustrated in FIG. 4. In most 2

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In 6 cases, the diameter (D) of the largest portion of the nodular assembly 3 is approx. 2 times the diameter (D1) of the thinnest portion immediately adjacent thereto. For each cm of the actual fiber length, 5 are formed between 0.1 and 0.5 nodular aggregates 3 having such a diameter (D). When the proportion of sheath 2 exceeds 55% by weight of the total weight of sheath and core, the formation of the aggregates 3 is not sufficient and, as a result, it does not contribute to any improvement in the grip of nonwoven fabrics.

Although there is no restriction on the fineness of the fibers, 1.5 to 7 denier is suitable for applications where emphasis is placed on the grip. Preferably, the range is easily between 0.7 and 7 denier. J

The hot-melt composite fibers of the invention are constructed as set forth above.

For the production of the hot-melt composite fibers of the invention, three polymers, namely, two polypropylene-based polymers for the core components and a polyethylene-based polymer for the sheath component, as previously mentioned in connection with the first aspect of the invention, are used. In connection with the polypropylene-based polymers for the core components, it can be stated that the polypropylene-based polymer for component 1a having a Q value of at least 6 should preferably exhibit a melt flow rate (hereafter sometimes abbreviated to MFR and measured according to Table 30). 1, condition 14, provided by JIS K 7210) of 4 to 40, and that the polypropylene-based polymer for component 1b having a Q value of 5 or less should preferably exhibit a melt flow rate of 4 to 60. polypropylene base having a Q value of 5 or less can be prepared by the following methods using polymers based on polypropylene having a Q value greater than 5 as the starting material. By

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7, a method makes but a combined addition and mixing of the starting polymer with an organic peroxide compound in an amount of 0.01 to 1.0% by weight, based on the starting polymer, whereby the organic peroxide compound releases oxygen by heating to a temperature equal to or greater than the melting point of the starting polymer, such as t-butyl hydroperoxide, cumene hydroperoxide or 2,5-dimethylhexane-2,5-dihydroperoxide, etc., and then the resulting mixture is subjected to melting temperature. extrusion from an extruder for granulation.

In another method, the starting polymer can be repeatedly subjected to melt extrusion at elevated temperatures without the addition of the aforementioned organic peroxide compound, so that repeated granulation is carried out. Since the Q value is slightly reduced by melt extrusion, the polymer to component 1a prior to melt spinning should preferably have a Q value slightly greater than 6, while the polymer to component 1b may have a Q value slightly larger. preferably, the polyethylene-based polymer should preferably have a melt index (hereafter sometimes abbreviated to MI and measured according to Table 1, Condition 4, provided by JIS K 7210) of between 2 and 50.

After providing the previously mentioned three polymers, they are separately fed to the respective three extruders for melt extrusion, and the resulting melted polymers are fed to a known suitable composite spinning nozzle by means of the respective gear pumps. A spinning nozzle such as the one described in Japanese Patent Publication No. 44-29522 can e.g. is used as the known composite spinning nozzle capable of spinning three polymeric components in a cross-sectional structure similar to the cross-sectional structure of the hot-melt composite fibers of the invention. When the aforementioned three polymers are supplied to such a spinning nozzle, the output amounts of the relevant gear pumps are regulated on such

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8, that the ratio of the amounts of the polymers for the core component 1a and 1b is given composite ratios within the range of 2: 1 to 1: 2, and that the amount of the polymer to the sheath component is within the range 5 between 25 and 55% by weight, based on the total amount of this and of the core components.

The non-stretched composite yarns thus obtained with the given cross-sectional shape are stretched in a single step or in the form of a multistage process. In order to increase the latent ripple properties of the composite yarns obtained, it is generally preferred that the stretching in the form of a multi-stage process is carried out such that the temperature below that stretching step is lower than the temperature during the second stretching step; and that in one single step the stretching is carried out at normal temperature (15 to 40 ° C) or at a relatively low temperature which is close to it. Since stretching is usually accompanied by heat generation, the stretching is preferably performed by an entrance process or in the first step of a multi-stage process while passing the yarns through water maintained at normal temperature or in a room maintained at normal temperature by means of cooling water.

The tensile conditions may vary somewhat depending on the hot melt composite fibers to be manufactured.

If it is desired to produce heat peelable composite fibers that meet only the previously specified minimum requirements set for the jacket, the tensile temperature may be within a range between normal temperature (15 to 40 ° C) and 130 ° C. The draw ratio is within a range between 1.3 and 9, preferably 1.5 and 6, expressed as the total draw ratio. In particular, the following stretching conditions7 are preferred, namely a stretching temperature which is the normal temperature, combined with a tensile ratio of 4 to 5 at the stretch in the first stage, and a stretching temperature.

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9 between 70 and 90 ° C combined with a draw ratio of 0.8 to 0.9 at the stretch in the second step.

If it is desired to produce the hot-melt composite fibers which meet the specified minimum requirements set for the sheath and which further have the aforementioned aggregate portions of the sheath 2, the stretching must be carried out using some somewhat more complicated steps. which is described below. Prior to stretching, the unstretched composite yarn is first heat treated without tension at a temperature between 80 ° C and a temperature below the melting point of the sheath component for 10 seconds or longer, preferably for 12 to 180 seconds. This heat treatment promotes the crystallisation of the components of the two cores 1a and 1b and reduces the interfacial affinity between the casing 2 and the core 1. Heat treatment can e.g. is carried out by continuously passing the yarns through an oven with dry heat or with hot water, or they can be discontinuously treated in a large drying apparatus. The heat-treated non-stretched yarns are cooled to room temperature (15 to 40 ° C) and the stretching in the first step is then carried out at this room temperature with a stretch ratio of 1.3 to 2, preferably 1.5 to 1.8.

By a synergistic combination with the specified heat treatment performed prior to stretching, the stretching in the first step supports a reduction of the interfacial affinity between the sheath 2 and the core 1. As a result, the sheath 2 is actually or latently released from the core 1 by the intermediate surface therebetween, thereby producing a number of the aggregate portions. At a tensile ratio exceeding 2 in the first stretching stage, problems such as lint formation, a reduction in fiber strength and an increase in shrinkage of the resulting nonwoven fabric appear, while a tensile ratio of less than 1.3 makes it difficult to achieve the effect sought by the invention. After the stretch in the first step, the stretch is carried out in the second

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10 steps without straining the yarn between the stretch in the first step and the stretch in the second step. This second step is carried out at a temperature of 80 ° C and above and below the melting point of the sheath component. In this case, the tensile ratio should be equal to or above 90 ° C of the maximum tensile ratio (at which the yarn drawn in the stretch in the first step begins to spring off by gradually increasing the tensile ratio in the second stretch When the fibers are stretched in the second step without tension after stretching in the first step, as previously stated, it is possible to prevent the fibers from being entangled due to the ripples that must be developed by fiber release and by the fibers cracking in addition to the stretch in the second step, in addition, the stretch in the second step, which is carried out at the pre-specified temperature and the pre-specified draw ratio, gives rise to the appearance of the three-dimensional ripple, by which the fiber strength is increased, the ripple rate and volume of the resultant nonwoven fabric are reduced and increased, respectively, and the formation of the aforementioned a gaggable parts are further encouraged.

When making the hot-melt composite fibers which meet the previously stated cutting requirements and which further exhibit aggregable parts, the grip thereof is made much softer if the unstretched yarns are used, the method of manufacture being set forth below. Thus, when performing a composite spin of three polymers, 30 is added a chemical agent to reduce the interfacial affinity (hereinafter referred to as the affinity reducing agent) to these polymers. More precisely, the affinity reducing agent is added to both polypropylene-based polymers for the two core components or to the polyethylene-based polymer for the sheath component or to both polymers for two core components and the sheath component. As such, affinity

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11 reducing agents, effective use of polysiloxanes such as polydimethylsiloxane, phenyl-modified polysiloxane, amino-modified polysiloxane, olefin-modified polysiloxane, hydroxide-modified polysiloxane and epoxy-modified polysiloxane and fluorine compounds such as per-fluoroalkyl group, perfluoroalkylene group containing polymers and modified products of these polymers. The affinity reducing agent is added to each of the polymers concerned in an amount of 0.05 to 1.0% by weight thereof. Thus, by stretching unstretched yarns produced by composite spinning with the addition of the affinity reducing agent to at least one of the polymers to the core and sheath components, the hot-meltable composite fibers can be made while further promoting the formation of the aggregable parts.

After the composite yarns have been stretched by stretching in a single step or in several steps, the 20 stretched yarns are dried if appropriate and can be used immediately or cut to a given length for the purpose intended.

From an efficiency point of view, the treatments of unstretched yarns, such as heating, cooling and stretching after spinning, should preferably be carried out with unstretched yarn bundles formed in the form of a preamble having a denier value corresponding to a greater number of times 10,000 to a greater number of times 1,000,000. It is also preferred to expose such a yarn to the given treatments, such as heating, cooling and stretching, while continuously feeding it at a low overall speed, without cutting the yarn into short fibers, if possible. . The treatments, such as heating, can be performed discontinuously, as already stated.

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12

EFFECTS

The hot-melt composite fibers of the invention are of composite nature, wherein the side-by-side type core to which two polypropylene-based polymers having different Q values are applied is covered with the sheath of the polyethylene based polymer having a melting point lower than the melting point of the polymers forming the core components. Although the 10 hot-melt composite fibers of the invention have a sheath core structure which, according to generally accepted opinion, exhibits reduced or limited development of ripples, the actual ripples and latent ripples developed by heating are very large. and they assume a moderate three-dimensional shape, because the core has side-by-side structure.

And because of the sheath core structure of the entire cross-section of the composite fiber, the composite fiber exhibits sufficient heat meltability with respect to the sheath, making it easy to produce bulky, high-volume nonwoven fabrics and stabilized structure upon heating.

In addition, when the sheath comprises many aggregatable parts, such parts are melted and aggregated by heating on the fiber surfaces, and then solidify to produce a number of nodular aggregates 3 consisting of the sheath component which impart a very soft to the nonwoven fabrics. grip. The reason seems to be that the contact area of the fiber surfaces is noticeably reduced, because the nodular aggregate 3 comes into 30-point contact with the surface of the adjacent fibers.

As a result, the hot-melt composite fibers of the invention further improve the volume and grip of nonwoven fabrics made therefrom, which have been problems associated with the prior art.

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13

EXAMPLES AND COMPARATIVE EXAMPLES

In the following, the invention will be further explained with reference to the Examples and Comparative Examples.

Ex. 1 to 12 and Comparative Examples 1 to 5

Eight polypropylenes a, b, c, d, e, f, g and h and two polyethylene-based polymers i and j listed in Table 1. were used in the combinations listed in Table 2. the positive fibers in which the composite core cores were side-to-side and formed by the core components 1a and 1b of two polypropylenes covered with the sheaths formed of a polyethylene-based polymer were made using the following treatments including composite spinning, heating and stretching.

The spinning nozzle used had 120 holes, each having a diameter of 1.0 mm. Components 1a and 1b constituting the core were used in a composite ratio of 1: 1, while the ratio of the sheath to the total amount of core plus sheath was varied in a range between 33.3 and 66.7 wt%. Referring to the spinning temperature (the polymer temperature just prior to spinning from the spinning nozzle), the polypropylenes for both components 1a and 1b and for the polyethylene-based polymer were spun at 250 and 220 ° C, respectively. In this way, non-stretched composite yarns of Ild / f (denier per filament) were obtained. The unstretched composite yarns were bundled into a yarn of approx. 90,000 denier and was stretched. Three-stage rollers were used for the stretch. The single-stage stretching was carried out by passing the barrel through the first and second stretching rolls, while the two-stage stretching was conducted by passing the barrel through the third stretching roller for the same

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14 the first stage stretch as the previously stated single step stretch The temperature of the first stage (identical to the stretch temperature in the case of the single stage stretch) is defined as being identical to the temperature of the first stretch roller, while the stretch temperature of the the second step is defined as being identical to the temperature of the second stretch roller. In this way, the yarn was passed through a bath containing 0.2% of a surface finishing agent at 21 10 ° C, and then passed through the first stretch roller at 26 ° C, the second stretch roller at 80 ° C, and the third stretch roller. at 28 ° C for a double-step stretch (e.g., 9 to 9, Comparative Examples 1-5), or it was passed through the second stretch roller at 70 15 ° C after the first stretch roller without using the other one. stretch roller, for single-step stripping. Then the products with a temperature higher than room temperature were cooled down to room temperature. The strength and elongation of the 20 heat-melting composite fibers thus obtained were measured while observing the shape of the ripples thereof. In addition, each heat-meltable composite fiber was used in an amount of 100% and heated to form a nonwoven fabric, the vo- luminosity of which was then tested in a sample.

25

The methods for these tests are set forth below.

Fiber Strength and Extension: 30 JIS L 1015 7.7 35

After heating to 145 ° C for 5 minutes, observers were observed

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visual assessment of whether each of the fibers in question was curled three-dimensional or two-dimensional.

Volume of nonwoven fabric: 5

A group of fibers is passed twice through a mapping machine to form a web with a surface weight of 100 g / m, from which five 25 cm x 25 cm square web pieces were cut. Each web piece was inserted between sheets of 10 kraft paper and the assembly was introduced into a circulating hot air dryer at a temperature of 145 ° C for 5 minutes to form a nonwoven fabric which was then cooled to room temperature.

Each non-woven fabric was cut to size 20 cm x 20 cm. Five such pieces were formed into a stack on which a piece of cardboard was arranged, and the thickness of a nonwoven fabric was calculated on the basis of the total thickness of the stack to find the value 20 expressed in mm for volume.

The results are shown in Table 2.

25 30 35 DK 161603 8 16

Table 1

Polymer Melt-Flow Q Value Point Capability (° C) 5 ----- a Polypropylene 162 MFR 8 7.4 b Polypropylene 162 MFR 10.2 6.6 c Polypropylene * 162 MFR 10.0 5.7 d Polypropylene * 162 MFR 12.2 4.5 e Polypropylene * 162 MFR 14.0 5.4 f Polypropylene * 162 MFR 22.0 4.9 g Polypropylene * 162 MFR 32.5 4.5 15 h Polypropylene * 162 MFR 34 , 0 3.6 in High density polyethylene 128 MI 19

Mixed polymer of 85% by weight high mass polyethylene (m.p .: 128 ° C, J MI: 19) with 15% by weight 127 MI 19.4% ethylene / vinyl acetate copolymer (ethylene content: 80% , and MI: 20) 25

Each starting polypropylene was modified by the addition of 2,5-dimethyl-2,5-di (ter-butyloxy) hexane and by extruding the product from an extruder for granulation. The starting polypropylenes c, d, e, f, and h had values of MFR of 6,4,6,18 and 4, respectively.

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18 On the basis of Examples 1 to 12 and Comparative Examples 1-4 set forth in Table 2, it was found that the development of three-dimensional ripples in the case that the two core components have the Q values that lie within 5 intervals defined by the invention are readily observable and the volume of the resulting nonwoven fabrics is excellent if other requirements correspond to the conditions of the invention. On the basis of Examples 6 to 12 and Comparative Example 5, it was found that the composite fibers obtained in accordance with the invention are excellent in all properties, including the development of three-dimensional ripples and the volume of the resultants, not -woven fabrics. On the other hand, when the proportion of the sheath differs from the range defined herein, the properties of the composite fibers stated are poor, whether the starting polymers are identical to or different from the ones used in the examples corresponding to the invention. Even in the case of single-stage stretching, it can be noted that the method of the present invention provides composite fibers which can be further processed into nonwoven fabrics of extremely excellent volume.

Ex. 13 to 22 and Comparative Examples 6 to 16 25

The same polymers as those used in Examples 1 to 12 and Comparative Examples 1 to 5 were used according to methods similar to those set forth therein to obtain the non-stretched yarns of composite fibers comprising various combinations as set forth in Table 3. However, in Example 15 0.10 wt% dimethylpolysiloxane was mixed with high-density polyethylene. The unstretched composite yarns were bundled into a pre-yarn with a denier value of ca.

90,000, which were then treated as follows: First, the preheater was heated by passing it without tension through a dry heating chamber at 105 ° C for 30 seconds (

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19, however, did not perform any heat treatment in Comparative Examples 6.7, 8 and 15 and Example 19.) Then, the preheat was left in a preheat container so that it could be cooled down to room temperature (22 ° C). Then, the pre-yarn was passed through a 21 ° C hot bath containing 0.2% of a surface finishing agent and it was subjected to stretching in the first step between a pair of cold pull features which are 26 ° C hot ( 60 ° C heat in Comparative Examples 12 and 90 ° C heat in Comparative Examples 14 and 15), at a draw ratio of 1.6. The pre-stretched yarn was successively transferred to the subsequent stretch in the second step without tension, and the pre-stretch was stretched between a pair of stretch rollers heated to 90 ° C (but with 15 different temperatures in Comparative Examples 10, 11 and 12), at tensile conditions corresponding to different percentages of different maximum tensile conditions during the stretch of the second step, as specified in Table 3, and were then cooled to room temperature. The strength and elongation of each of the heat-meltable composite fibers thus obtained were measured, while observing the shape of ripples and the degree of aggregability of the jacket. Further, each hot-melt composite fiber was used in an amount of 100% and heated to form a nonwoven fabric, the volume of which was then examined by a sample.

The test methods for these tests, with the exception of the samples already explained, are shown below.

Degree of aggregability

After heating the composite fibers to 145 ° C for 5 minutes, 100 fibers were observed, each having a length of approx. 3 to 12 cm, under an optical microscope. The assessment was made using the following reference numerals.

DK 161603B

20 numbers 1,2,3 and 4, based on an average number of the nodular aggregates per cm of actual fiber length, which aggregates had a maximum portion having a diameter at least twice the minimum diameter 5 of the thinner part adjacent to the nodular assembly.

1: 0.30 or more • 2: 0.10 to 0.29 10 3: 0 01 to 0.09 4: below 0.01

Grip of Nonwoven Fabric 15 The grip of the nonwoven fabrics obtained in accordance with the methods listed in connection with the Non-woven Fabric Volume "was examined by a panel of 5 persons comparing with the grip of the non-woven fabric serving as blank.

20 The rating was made on the basis of the following numerical values (majority rating): 1: The softness was excellent 2: The softness was relatively good 25 3: The softness was largely identical 4: The softness was low and had a hardness character

The previously referenced non-woven fabric for evaluation of the grip was obtained on the basis of the composite fibers of Comparative Example 15, wherein the non-stretched yarn was stretched substantially according to the prior art.

The results are shown in Table 3.

35 21

DK 161603 B

I JJ * · XI O) 0) 4-1

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p tho flj I v

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ri π y Λ> O '* * * *' '' '- ** 0 · η <u .M fU · ρ co co n · ^ h · r> hhh · r * · Tt <ro co co ro co tf > r- tf) inr * ·> £ -p -π> ω 1 P * 0 0) aj ο

* 0 «I O), £ Tf Tf Tf CO CN rl rl (Μ Η H (O CO CO CO Tf Tf Tf CM CN COH

ιΰ t) U

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«0 <W CM CM CM CM O) CO CO CO CO CO <0 CO CM CO CM CMCMCOCO CMCO

J (3 (N o CO ΓΊ O co CO O co Tf O CO t- * Tf H CO CO CO tf) O N

aik µ the Tf Tf Tf TfTfTfTftntntf) O) r- tf) t "® co Tf tf) tf) tf) Tf XOI l« P m 0) tt) 0) »>, cæ O) σ> O οι (NOOO co (D Tf tf) tf> CO Ό O 'CO O' CO Γ 'CTi • p οι whm tj * * * * * * * * * * * * * * * *% * · · * {/] O Η II β S. CO co Tf Π) ^ Μ * M * Tf (O CO (N CN CO CM CM CO CO CO CO C0C0 o> CQ O CO CO CO CO ri CO Tf rH «Η Tf O CM ri HH (4 ri H ri ri Tf «ν, κο O 'σ σ * σ σ cm σ σ σ σ σ σ σ co r- σ σ σ σ σ

tf H

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X G co t * r co φ οι ίο σι oi o o «co cm vo vo in m o o σι σ σ (¾ · · Η k * * ******* *» * * * **** **

s l Ό IN 4 CM CM CM CM CM CM CM CM CO CM H CM CM CM CM CO CO CO CM CMCM

(UH 4 · »X o J £ .C C CO tf) CO ifl ΙΟ Ό ΙΟ ΙΟ Ά <0 tf) VO VO tf) VO tf) tf) tf) tf) Φ Φ

y ^^ v * * ******* * * * * «> *« «» * »<U

Ρ 0 Η P ri ri ri H ri ri ri ri ri Η H ri ri ri HHHH HHG

Η Ή jj ρ r * 3 G & I + J.-HO o OOOOOOOO tf) OOOOOOOO 006 vtøcMh 0) 0) o> O) ø) o * <7) ø) o Q) cm r * i '* θ' ο »σ σ 'σ σ σ σ αι X u ν« X υ · * y ^ jj ft)

U Ε · τ4 CO CO tf) <D tf) tf) tf) tf> tf) tf) cO tf) O CO O Otf) tf) tf) Φ Φ II

P ft) rl P CM CM CM CMOJCMCMCMCMCM CM CM tf) CM O 'O' CM CM CM CM CM 0)

Cfl -P -P 5

I I

T3tn d O CM O rl HOCOHCMOH rl rl rl rl rl HHHH HOG

¢) β ft a + j r * * * * ******* * * * * * .. ** ** σ J-.H q. e f h CM <M CM CM CM CM CM CM CM CM CM CM CM CM CM (N CM (N CM (M tf) Ή

¢) ¾ (OOlUS CM CM CM CM CM CM CM CM CM CM CM CM CM CM CMICMCMCMCM CM CM H

Π .Z Φ <0 05 ft H CN Tf Tf fs Ο O rH CO Tf CM CM O CM CM CN CN CN CM CNCNg * dj * * * ******* * * * * * **** ' * 60

rrt CO CO VO tf) H rl σ rH tf) CO rl Η Η Η H HHHH Η Η (0 H

(UG IIP H rl Η Η H CN CM CM Tf Tf rH Tf Tf Tf Tf Tf TfTfTfTf Tf Tf (0 H

-O flJ U A tt W

GOt-PK O CM O OHOHCMOCN O O CO Ο O OOOO 00 * H> i (μ P β β * * * ******* * * * * * **** ** rl

OJ o <D ε * 0 CN CN fr- |> - N N (N (N IN> Γ- I "* 1 ^ - Γ- Γ * ΓτΓτ · Γ ^ r * c ^ - PO

sJ ^ G · ^ Η H rl rl rHHHrlHrlrl rH Η Η H rl HHHH rl rl 11 ft P> 1 ii µ o co co co co o co σ cm cm σ O 'O' O 'σ σ σ σ σσΦΛ φ c ft) ο) yes * * * ******* * * * * * **** ** ^ ν • HG Φ «Ρ C Η Ό tf) tf) tf) tf) in Tf co CO Tf CO co co co co CO CO CO CO CO 01 cn ft 1) Ό PG 4H * H 0 β P ft) 0 ft) Ό 'Si

9A M Cb G CM (Μ Η H CM CM CM CM (Μ Η Η H rl Η H HHHH HHjUO

^ Ή O ft) ft H fr I "·» tf) tf) t ^ - Γ 't' ·· r ^ · Γ'- CD cO CO cO Ό VO VOvOvOO vOvOJ ^^ C

ΟΙ φ X «Ρ wli ^ σ H 0) 1 CO CO CO CO co co CO CO CO CO CO CO CO co <0 CO COCO t- * CO <0tø UJrQjJ * * * ******* * * * * * ** ** >> Ό (uoi ro ro co cncocococococo co co co co co cocoinin voco

G q-ι .¾ # co tø tø cocotøtocococo co co co co co cocoTfin cocoPO

tf nj w> g i P o 1) 0 * * ft A -P * o> w H ft g G Η -r | · Η * H · Η * H · H Μ H * rl Ή · Η · Η Η · Η · Η Ή · Η · Η Η · η 1) µ · Η «Ο U *" 2 (1) Μ .XX β S ® f X Ό

►>, IIP Λ Λ Ο Ο ϋϋί) * Η0) ΛΌ Ο) 0) θ '0) 0) 0) 0) 0) 0) 0) 0) <AND

Η II Ο II Η ft ® ο c Οι 4J *! rj CU Η Ρ β G ω Λ • Η (1) Ο Φ <0 Φ <0 Λ J3 ιΰ (d Ιΰ Ιΰ Φ Λ J3 Λ Λ Λ XI XJ XI XI X) X) X) Η £ -. Βί Λί β Η

co ♦ ♦ ♦ ¥ It X V

tf> r *. co σ 'co Tf mu) c ^ · co oh cm co Tf in σ oh vo n ^ rH ΗΗΗΗΗΗΗΗΗΗΗΗΗΓΜΓΜ ΗΓΜτΙΡ φ ......................... ....... Φ

n rHMHUHWHWWUWWWUHUHMHWHWHttHWlOWCOHWlOlUQ

* 3 EX EX EX EXXXXXXX EX EX EX EX EX EX EXXXXEXXa * HU) ft) (aft) toft) toft) ft) ft) a) ft) tifti (aa) (aft) (aft) (aa) to4) ieiuft) ft ) ft) tftft) ft) ** i DK 161603 B j 22 i | On the basis of Examples 13 to 22 and Comparative Examples 6 to 9 given in Table 3, it was found that the development of three-dimensional ripples in the cases where two core components have the Q values which are 5 within the range, those defined by the invention are readily observable and that the volume of the resulting nonwoven fabrics is excellent if other requirements correspond to the conditions of the invention. Examples 13 and 14 show that composite fibers can be obtained with 10 much better aggregability, i.e. formation of nodular aggregates other than those made otherwise / if affinity reducing agent such as polysiloxane is added to the polymer serving as a raw material during manufacture. By comparing 15 Examples 19 to 21 and Comparative Examples 10 to 16, it can be seen that the composite fibers obtained using the method of the invention are excellent in the development of three-dimensional ripples and in terms of high volume of the resulting non-volumetric ripples. woven fabrics. On the other hand, when the proportion of the sheath, the use of heat treatment of unstretched yarns, the stretching temperature and the draw ratio differ from the ranges defined herein, the properties of the composite fibers previously stated are poor, even if the same starting polymers are used. By comparing Examples 20 and 21 to Example 19, it is seen that the composite fibers obtained by using the heat treatment prior to stretching the non-stretched composite yarns exhibit more excellent aggregability properties and, as a result, also 30 in terms of grip of the resultant nonwoven fabrics than those made without this heat treatment. Thus, it has been found that the heat treatment of the unstretched composite yarns greatly affects the aggregability.

35 23

DK 161603 B

Application Samples Sample Group 1 5 The hot-melt composite fiber (2.9 d / f) obtained according to Example 3 was cut to a length of 64 mm and mixed with rayon with the characteristic 2d x 51 mm in the proportions , which is given in Table 4. A nonwoven fabric with a surface wall approx. 100 2 10 g / m was prepared largely according to the methods of testing the previously stated "volumetric nonwoven fabric" and it was tested for volume and measured for strength and elongation.

15 Test Methods

Volume of nonwoven fabric:

The same methods as in Examples 1 to 12.

20

Strength and extension of non-woven fabric:

Five specimens with the dimensions 20 cm x 5 cm were cut out of the nonwoven fabric in such a way that their 25 sides with the dimension 20 cm lie along the direction of movement of a map machine. The fracture strength and elongation of the five specimens are determined with a fracture strength specimen with a clamping gap of 100 mm and a tensile speed of 100 mm / minute, and the averages 30 of the individual measurements are calculated.

The results are given in Table 4.

35

DK 161603B

24

Table 4 --------, ----,

Mixing ratio Weight Volume- Strength Extend-

Ingredient (weight 4 o):,, nausea, six-test ---------. Compo- (mm) (kg / 5em) (%)

You sit- Rayon I

5 J fibers · j | ----- j -——--------- j 1 10 90 99 3.7 0.25 185 2 20 80 97 3.9 0.36 136 - 3 ~ ~ i 30 I 70 102> 5 ~ 9 1 02 92

S 3 J

----, -: ------ 1 -----.-: --- 10 4 40 60 98 6.4 2.70 .94 5 60 '40 100 6} 8 3.28 83

6 80 “To 104 TI TTl 76 I

__________> ___ '_i 7 100 0 98 Τβ 7 96 Γ ~ 66 i

____ '' I

15 On the basis of a comparison between application samples Nos. 1 to 2 on the one hand and Nos. 3 to 7 on the other, as shown in Table 4, it appears that the nonwoven fabrics formed from the mixtures of the hot-meltable composite fibers of the invention with other fibers, such as rayon, are excellent in terms of volume and strength when the composite fibers are used in an amount of at least 30% by weight.

Test Group 2 25

Except for the use of the hot-melt composite fibers obtained according to Example 16, instead of those obtained according to Example 3, sample group 1 was repeated for the production of nonwoven 30 fabrics which then our volume and grip were tested, and whose strength and extension were measured. The non-woven non-woven fabric for judging grip was similarly prepared using 30% by weight of the composite fibers obtained according to Comparative Example 15 and 70% by weight rayon.

25

DK 161603 B

Test methods (except the previous ones)

Handles of nonwoven fabric: 5 The same as in Examples 13 to 22.

The results are given in Table 5.

10 Table 5 | ---------- 1 ~ f --- 1 —--—---, j Mixer- Weight- Grab Volume- Strength 'Relative to Nosiness | ι „η 16 _ [weight - «: __; (g / m2i (“) (kg / Scm) yield sample Component Rayon (¾) _nr '___fiber _.___ 1_ 8 1 ° 102 4 3.8 0) 21 180 9 20 80 100 3 3, 9 0.32 120 20 ---—-- 10 30 70 98 2 5.8 ^ beers 90 11 40 60 100 2 6.3 ~ 2 2 58 90 12 60_ 40 98 2 6.8 3, * 04 ~ 84 13 80 20 101 * i | 1} 1 '* [100 I 0 | 100 I 1 [7.7 7.76 68

Non-30 70 98 - 3.4, J08 94 I ----- ^ ---- 1 - ^ ---- 1 --- ^ --- L__i 30 35 26

DK 161603 B

On the basis of a comparison between the application samples Nos. 8 to 9 on the one hand and Nos. 10 to 14 on the other, cf. Table 5, it has been found that the non-woven fabrics made from the mixtures of The hot-melt composite fibers of the invention with other fibers, such as rayon, are excellent in grip, volume and strength when the composite fibers are used in an amount of at least 30% by weight.

10 15 20 25 30 35

Claims (9)

A hot-melt composite fiber comprising a polypropylene core member 5 and a polyethylene jacket member, characterized in that the core member itself has side-by-side composite structure and comprises two different core components. on the basis of polypropylene in a composite ratio of 1: 2 to 2: 1, with one of the core components (1a) having a Q value expressed as (average molecular weight by weight) / (average molecular weight by number) equal to or greater than 6, and the other (1b) having a Q value equal to or less than 5 and the polyethylene jacket having a melting point at least 20 ° C lower than the melting point of the two core components, it is the lowest that it constitutes from 25 to 55% by weight, 20 based on the total weight of the sheath portion and the core portion, and that it covers the core portion. Heat-meltable composite fiber according to claim 1, characterized in that the jacket exhibits a number of aggregate parts which can be released at least latently and which, in a heat treatment at a temperature higher than the melting point of the jacket component, but lower than the lowest melting point of the two core components, many nodular aggregates form thereon. 30 A hot melt composite fiber according to claims 1 to 2, characterized in that the polymer based on polypropylene in at least one of the two core components is a homopolymer. 35 A hot-melt composite fiber according to claims 1 to 2, characterized in that the polymer based on DK 161603 B polypropylene of at least one of the two core components is a copolymer of propylene with a small amount of an alpha-olefin which is not propylene. Process for the production of hot melt composite fibers according to claims 1-4, characterized in that during the use of a suitable spinning nozzle, by melt spinning, an unstretched yarn of composite filaments having a core part having -10 side-by-side positive structure and consists of two core components with a composite ratio of 1: 2 to 2: 1, one of the core components having a Q value expressed as (average molecular weight by weight) / (average molecular weight by number) equal to or greater than 6 and the other having a Q value equal to or less than 5, said core portion being covered with a polyethylene-based sheath portion comprising 25 to 55% by weight, based on the total weight, of the sheath and core portion 20, upon which the resulting unstretched composite yarn is stretched by a stretching process performed in one or more steps. Process according to claim 5, characterized in that the non-stretched composite yarn before stretching, without being subjected to any stress, is heated to a temperature above 80 ° C, but below the melting point of the sheath component for 10 seconds or longer and cooled. 30 to room temperature and then subjected to stretching in a first stage at room temperature and having a draw ratio of 1.3 to 2, after which it is subjected to stretching in a second stage at a temperature of at least 80 ° C, but below the melting point of the sheath component and having a tensile ratio of at least 90% of the maximum tensile ratio of the stretch in the second step. DK 161603 B Process according to claim 6, characterized in that at least one material selected from polysiloxanes and fluorine compounds is added to at least one of the three components of the composite yarn during an amount of between 0.05 and 1.0% by weight during the composite spinning step. , based on the polymer (s), after which the resulting unstretched composite yarn is stretched. Process according to claims 5-7, characterized in that the polypropylene component having a Q value of 6 or more has a melt flow rate of between 4 and 40. Process according to claims 5-7, characterized in that the polypropylene component having a Q value of 5 or 15 below has a melt flow rate of between 4 and 60. 20 25 30 35